The present invention relates broadly to coupling assemblies for releasably joining conduit sections, such as pipes and hoses in axial, end-to-end relationship. More particularly, the invention pertains to a safer and better sealed coupling assembly for breakably connecting opposed end structures of the conduit sections such as used in concrete pumping systems.
Concrete pumping systems are used in placement of concrete in various applications. The present invention has been particularly applied to the concrete pumping technology but may of course be used in other conduit lines which transport like highly mechanically abrasive and wear creating fluid materials under typical pressures of 500 to thousands of pounds of pressure per square inch (psi). In boom mounted units, the booms are formed of tubes to form a part of the pumping line. Hereinafter, conduit is generically used to include any tubular member, such as a pipe or hose, which is interconnected to form a part of the line. In concrete pumping, excessive wear of the conduit is a common problem, and a special problem at the coupling of the conduit sections, particularly where there is a change of flow direction.
In concrete pumping systems, conduit sections are interconnected to each other with releasable couplings. A typical system is disclosed in U.S. Pat. No. 3,705,737, which issued Dec. 1, 1972 and U.S. Pat. No. 4,305,607 which issued Dec. 15, 1981, to the assignee of this invention. The coupling of the conduits in present technology generally include a multiple part, releasable clamp assembly, such as a hinged C-shaped clamp unit with a sealing gasket located within the coupling to seal the joint between slightly spaced conduit ends of the line. Thus, the conduit ends will normally be spaced slightly from each other and sealed by special surrounding gasket structures. The conduit ends universally include an end body member which has an annular groove, with the side edges of the U-shaped clamp members fitting within the grooves and locking the conduits to each other.
Unfortunately, it has been found that because of the shallow depth of the annular grooves in the conduit ends, the engagement surface areas of the side edges of the coupling clamp members with the grooves, and the working pressure of the pressurized fluid flowing through the conduit lines, there is a greater possibility of bursting at the conduit end than desired. In addition, it has also been discovered that the gasket design of the prior art coupling can restrict the working pressure in the conduit line and lead to premature leaking.
Accordingly, it is desirable to provide an improved conduit end structure which cooperates with the coupling and gasket to avoid the drawbacks of the prior art.
It is a general object of the present invention to provide an enhanced conduit coupling arrangement for concrete pumping systems which reduces the possibility of bursting and leaking during high pressure operation.
It is one object of the present invention to provide a conduit end interposed between a coupling and a gasket within the coupling in a wedge and seal relationship.
It is another object of the present invention to provide a conduit end having a flared construction.
It is also an object of the present invention to provide a coupling having a gasket which allows for a higher working pressure when placed within a conduit line.
It is a further object of the present invention to provide a unique method of assembling a coupling arrangement.
In one aspect of the invention, a coupling arrangement is provided for permitting fluid-tight, pressurized fluid flow therethrough. A pair of conduit members is located in end-to-end relationship, each of the conduit members having a flared end. An encircling coupling unit surrounds the ends of the coupling of the conduit members and has structure to tighten the coupling unit around the flared ends of the conduit members. The coupling unit has inner lateral surfaces partially defining a coupling cavity. An encircling, deformable gasket is disposed in the cavity of the coupling unit. The gasket has exterior lateral surfaces spaced from the inner lateral surfaces of the coupling unit and interior surfaces defining an annular recess therein. A rigid ring liner is retained within the annular recess of the deformable gasket to reinforce the gasket. The flared ends of the conduit members are engaged in wedging and sealing relationship between the inner lateral surfaces of the coupling unit and the exterior lateral surfaces of the deformable gasket.
In a preferred embodiment, at least one of the conduit members includes a hose and at least one of the other conduit members includes a pipe. The flared ends are bent generally at an angle of between 90 degrees and 109 degrees relative to a longitudinal axis of the coupling unit. The flared ends include axially extending sections to which the hose and pipe are secured. The coupling unit is formed by a pair of coupling sections pivotally connected together. Each coupling section includes a set of axially extending outer faces connected to a set of radially extending stepped portions, in turn, connected to a set of axially extending stepped portions. Each coupling section includes a base defining an inner diameter of the coupling section, the base having a pair of opposed ends. Each coupling section includes a set of inclined side walls connecting one end of the base with the axially extending stepped portions. The inclined side walls diverge from the base to the axially extending stepped portions. The inclined side walls define the inner lateral surfaces of the coupling unit. The inclined side walls and the base define a generally frustroconically-shaped coupling cavity for receiving the flared ends of the conduit members and the gasket therein. The deformable gasket is a resilient, rubber-like ring member centrally positioned in the coupling cavity. The gasket includes an outer end wall defining an outer diameter of the gasket, the outer end wall being engageable with the base of each coupling section. The gasket further includes a set of vertical sidewalls connected to the outer end wall by a set of angular shoulders. The set of vertical sidewalls and the set of angular shoulders define the exterior lateral surfaces of the gasket. The gasket further includes a set of inner faces extending radially from the set of vertical sidewalls. The gasket is formed with an annular recess for receiving and maintaining the ring liner therein. The inner faces define an inner diameter of the gasket when the ring liner is retained in the annular recess. The annular shoulders and vertical sidewalls are spaced inwardly from the inclined side walls of each coupling section. The inclined side walls of the coupling sections are formed at an angle of about 19 degrees relative to the axially extending step portions. The angular shoulders of the gasket are oriented at an angle of about 26 degrees relative to the vertical sidewalls of the gasket.
In another aspect of the invention, a coupling arrangement for permitting fluid-tight, pressurized fluid flow therethrough includes a pair of conduit members located in end-to-end relationship. An encircling coupling unit surrounds the ends of the conduit members in a tightened closure thereon and has inner lateral surfaces partially defining a cavity. A resilient gasket is disposed in the cavity and has exterior lateral surfaces thereon. The invention is improved wherein the conduit members have flared ends engaged in wedging and sealing relationship between the inner lateral surfaces of the coupling unit and the exterior lateral surfaces of the gasket whereby an increase in the pressure of fluid flow through the conduit members will increase the degree of wedging and sealing relationship of the flared ends between the coupling unit and the gasket.
In yet another aspect of the invention, there is contemplated a method for assembling a coupling arrangement including the steps of:
a) providing a pair of conduit members in end-to-end relationship, each of the conduit members having a flared end;
b) supplying an encircling coupling unit having inner lateral surfaces partially defining a cavity in the coupling unit;
c) placing the flared ends of the conduit members inside the coupling unit adjacent the inner lateral surfaces thereof;
d) providing a deformable gasket having exterior lateral surfaces and an annular surface for retaining a ring liner therein; and
e) positioning the deformable gasket and ring liner in the cavity of the coupling unit between the flared ends such that the flared ends of the conduit members are in wedging and sealing relationship between the inner lateral surfaces of the coupling unit and the exterior lateral surfaces of the deformable gasket.
Various other objects, features and advantages of the invention will be made apparent from the following description taken together with the drawings.